Duckbill aerosol separator with always open refinement

ABSTRACT

An impactor separator comprises a housing having an inlet receiving a gas-liquid stream and an outlet expelling a gas stream. The impactor separator also includes an impaction surface positioned within the housing and configured to separate liquid particles from the gas-liquid stream and a nozzle assembly positioned within the housing. The nozzle assembly includes a nozzle assembly housing portion and a plurality of nozzles extending through the nozzle assembly housing portion. Each of the plurality of nozzles includes a nozzle inlet and a nozzle outlet. The gas-liquid stream enters into the nozzle assembly housing portion, flows into the plurality of nozzles through the nozzle inlet and exits the plurality of nozzles through the nozzle outlet. The plurality of nozzles accelerates the gas-liquid stream toward the impaction surface.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Phase of PCT Application No.PCT/US2020/019175 filed Feb. 21, 2020, which claims the benefit ofpriority to U.S. Provisional Application No. 62/817,289 filed Mar. 12,2019. The contents of these applications are incorporated herein byreference in their entirety and for all purposes.

TECHNICAL FIELD

The present disclosure relates generally to inertial impactor separatorassemblies.

BACKGROUND

Internal combustion engines generally combust a mixture of fuel (e.g.,gasoline, diesel, natural gas, etc.) and air. During operation of aninternal combustion engine, a fraction of combustion gases, calledblowby gases, can flow out of the combustion cylinder and into thecrankcase of the engine. The blowby gases can include a mixture ofaerosols, oils, and air. The blowby gases are typically routed out ofthe crankcase via a crankcase ventilation system. To separate liquidparticles from the blowby gas, an inertial gas-liquid impactor separatormay be used. Using an inertial gas-liquid impactor separator, liquidparticles are removed from the blowby gas by accelerating the blowby gasto high velocities through nozzles or orifices and directing the streamor aerosol against an impactor.

Using various conventional impactor separators, a cold start or coldoperation may be difficult. During a cold start or operation of anengine in a very cold climate, the small orifice nozzles of the impactorseparator may pose a freeze-up risk, where front builds up on adischarge side of small nozzles and begins to at least partially blockthe fluid flow through the nozzles. This blockage causes rising pressuredrop across the separator and detrimental consequences can ensue, suchas opened bypass valve (to dump unfiltered blowby and aerosol toatmosphere), blow-out dipstick, bulged valve cover, etc. The problem ismost pronounced when orifice size becomes quite small, approximatelyless than 3 millimeters, which is unfortunate because impactionseparation performance is known to improve with smaller nozzle orificediameter. Many conventional impactor separators also require the use ofvarious moving parts such as poppet valves, springs, rotating orificeplates, sliding pistons, etc., which are subject to on-board diagnosticrequirements.

SUMMARY

Various example embodiments relate to an impactor separator comprising ahousing having an inlet receiving a gas-liquid stream and an outletexpelling a gas stream. The impactor separator also includes animpaction surface positioned within the housing and configured toseparate liquid particles from the gas-liquid stream and a nozzleassembly positioned within the housing. The nozzle assembly includes anozzle assembly housing portion and a plurality of nozzles extendingthrough the nozzle assembly housing portion. Each of the plurality ofnozzles includes a nozzle inlet and a nozzle outlet. The gas-liquidstream enters into the nozzle assembly housing portion, flows into theplurality of nozzles through the nozzle inlet and exits the plurality ofnozzles through the nozzle outlet. The plurality of nozzles acceleratesthe gas-liquid stream toward the impaction surface.

Other example embodiments relate to an impactor separator. The impactorseparator is formed as part of a valve cover. The impactor separatorincludes a nozzle assembly positioned within the valve cover and aplurality of nozzles, each of the plurality of nozzles having a nozzleinlet and a nozzle outlet. A bottom portion of the valve cover includesan inlet receiving a gas-liquid stream. The impactor separator includesan impaction plate having an impaction surface structured to separateliquid particles from the gas-liquid stream. The gas-liquid streamenters into the valve cover, flows into the nozzles through the nozzleinlet and exits the nozzles through the nozzle outlet. The plurality ofnozzles accelerate the gas-liquid stream toward the impaction surface.

Still other example embodiments relate to a nozzle assembly. The nozzleassembly includes a nozzle assembly housing portion having alongitudinal axis and multiple nozzles extending through the nozzleassembly housing portion, each of the nozzles having a nozzle inlet anda nozzle outlet. One of the nozzles is positioned along the longitudinalaxis and includes an always-open orifice.

These and other features, together with the organization and manner ofoperation thereof, will become apparent from the following detaileddescription when taken in conjunction with the accompanying drawings,wherein like elements have like numerals throughout the several drawingsdescribed below.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a cross-sectional view of an inertial impactor separator,according to an example embodiment.

FIG. 2 shows a perspective view of a nozzle assembly for use with theinertial impactor separator of FIG. 1 , according to an exampleembodiment.

FIG. 3 shows a perspective view of another nozzle assembly for use withthe inertial impactor separator of FIG. 1 , according to an exampleembodiment.

FIG. 4 shows a cross-sectional view of the nozzle assembly of FIG. 3 .

FIG. 5 shows a perspective cross-sectional view of the nozzle assemblyof FIG. 3 .

FIG. 6 shows a top view of a nozzle for use with a nozzle assembly ofthe inertial impactor separator of FIG. 1 , according to an exampleembodiment.

FIG. 7 shows a side view of the nozzle of FIG. 6 .

FIG. 8 shows a top view of a nozzle for use with a nozzle assembly ofthe inertial impactor separator of FIG. 1 , according to an exampleembodiment.

FIG. 9 shows a side view of the nozzle of FIG. 8 .

FIG. 10 shows a top view of a nozzle for use with a nozzle assembly ofthe inertial impactor separator of FIG. 1 , according to an exampleembodiment.

FIG. 11 shows a side view of the nozzle of FIG. 10 .

FIG. 12 shows a top view of a nozzle for use with a nozzle assembly ofthe inertial impactor separator of FIG. 1 , according to an exampleembodiment.

FIG. 13 shows a side view of the nozzle of FIG. 12 .

FIG. 14 shows a perspective view of the inertial impactor separator ofFIG. 1 in use in a valve cover of an internal combustion engine,according to an example embodiment.

FIG. 15 shows a perspective cross-sectional view of the inertialimpactor separator of FIG. 14 .

FIG. 16 shows a perspective view of a nozzle assembly of the inertialimpactor separator of FIG. 14 , according to an example embodiment.

FIG. 17 shows a top view of the nozzle assembly of FIG. 16 , accordingto an example embodiment.

FIG. 18 shows a front view of fluid flow through the nozzle of animpactor separator using computational fluid analysis, according to anexample embodiment.

FIG. 19 shows a top view of fluid flow through the nozzle of an impactorseparator using computational fluid analysis, according to an exampleembodiment.

FIG. 20 shows a graph illustrating the effect of a rectangular nozzleaspect ratio on the Stokes number, according to an example embodiment.

FIG. 21 shows a top view of a portion of a nozzle assembly of theinertial impactor separator of FIG. 1 , according to an exampleembodiment.

FIG. 22 shows a perspective view of the nozzle assembly of FIG. 21 .

FIG. 23 shows a graph illustrating the effect of various impactor nozzletypes on pressure drop relative to fluid flowrate, according to anexample embodiment.

FIG. 24 shows a graph illustrating the effect of various impactor nozzletypes on efficiency relative to fluid flowrate, according to an exampleembodiment.

DETAILED DESCRIPTION

Referring to the figures generally, an inertial impactor separator isshown. The inertial impactor separator includes a nozzle assembly and animpaction surface. The inertial impactor separator receives a gas-liquidstream, for example, blowby gases from an internal combustion engine.The inertial impactor separator removes liquid particles from thegas-liquid stream by moving the stream through a nozzle assembly andtoward the impaction surface. The nozzle assembly increases the speed ofthe gas-liquid stream and forces the stream onto the impaction surface,where the stream undergoes a sharp change in direction, effectivelycausing a separation of liquid particles from the gas-liquid stream.

The inertial impactor separator described herein separates submicron oilaerosol from engine blowby gas at a relatively high efficiency without amoving poppet valve and/or spring and without creating excessivepressure drops at initial engine or worn-out engine flow rateconditions. The separator allows for cold start and/or cold operation ofan engine without the risk of small nozzle freeze-up. The separator andnozzle assembly described herein exhibit a nearly linear pressure dropversus flow response as compared with a quadratic response of a fixedimpactor. In this way, a much wider flow range at a given maximumpressure drop limit is achieved.

Referring to FIG. 1 , an inertial impactor separator 100 is shown,according to an example embodiment. The impactor separator 100 includesa housing 102 having a longitudinal axis 115, an inlet 120 for receivinga gas-liquid stream 101, and an outlet 130 for discharging a gas stream111. The housing 102 includes a housing bottom portion 104 and a housingtop portion 106 coupled together to form the housing 102. A housingcavity 103 is defined by an inner surface 107 of the housing top portion106 and an inner surface 109 of the housing bottom portion 104. In someembodiments, the housing 102 is made of a single portion.

A nozzle assembly 110 is positioned within the housing cavity 103 alongthe longitudinal axis 115. The nozzle assembly 110 is formed by a nozzleassembly top portion 116 and the housing bottom portion 104. The nozzleassembly top portion 116 includes a bottom end 124 configured to beinserted into (e.g., coupled to) a slot 114 formed in the housing bottomportion 104. A nozzle assembly cavity 113 is defined by an inner surface117 of the nozzle assembly top portion 116 and the inner surface 109 ofthe housing bottom portion 104. In some embodiments, a flange 112 isformed with the nozzle assembly top portion 116.

The nozzle assembly 110 includes multiple nozzles 150 positioned in andextending through the nozzle assembly top portion 116. In the embodimentdepicted in FIG. 1 , the nozzles 150 are duckbill valves. In otherembodiments, the nozzles 150 may be another type of nozzle. The nozzles150 each include a nozzle inlet 151 positioned in the nozzle assemblycavity 113 and a nozzle outlet 152 positioned in the housing cavity 103.Fluid flowing through the separator 100 enters the nozzle 150 at thenozzle inlet 151 and exits the nozzle 150 through the nozzle outlet 152.As shown in FIG. 2 , the nozzles are oriented such that the nozzleoutlet 152 (e.g., slit) is oriented radially toward the longitudinalaxis 115 or toward the center nozzle 154 described below. In this way,the potential for flow interference between fluid flow exiting each ofthe nozzles 150 is reduced.

The fluid flowing through the nozzles 150 flows in a directionsubstantially parallel with the longitudinal axis 115 of the separator100. The nozzles 150 receive the gas-liquid stream 101 and acceleratethe gas-liquid stream through the nozzles 150 toward an impactionsurface 108. The fluid exiting from the nozzle outlet 152 flows in adirection substantially parallel with the longitudinal axis 115 andsubstantially perpendicular to the impaction surface 108. The impactionsurface 108 is positioned on the underside of (e.g., as part of) animpaction plate 118 having a rim or lip 122 (e.g., downward projectionat the perimeter). In some embodiments, the impaction plate 118 may beformed integral with the housing top portion 106.

The impaction surface 108 includes a fibrous and porous structure (e.g.,felt-like). This type of structure improves overall separationefficiency relative to a smooth non-porous impaction surface. Thefibrous and porous structure of the impaction surface 108 describedherein causes both liquid particle separation from the gas-liquid streamand collection of the liquid particles within the impaction surface 108.The porous impaction surface 108 has a cut-off size for particleseparation which is not as sharp as that of a smooth non-porous impactorimpingement surface but improves collection efficiency for particlessmaller than the cut-off size as well as a reduction in cut-off size.The porous impaction surface 108 provides a coalescing medium, such thatliquid particles, once captured within the impaction surface 108, willcoalesce with other liquid particles in the impaction surface 108. Inaddition, the accelerated gas stream and resultant high velocity of gasat and within the impaction surface creates drag forces sufficient tocause captured liquid to migrate to the outer edges of the impactionsurface 108 and to shed off of the impaction surface 108.

The porous impaction surface 108 has high permeability, thereby allowingthe gas-liquid stream to penetrate the porous collection surface. Insome embodiments, the permeability of the porous impaction surface 108is at least 3.0 e-10 m². In some embodiments, the permeability of theporous impaction surface 108 is at least 4.5 e-10 m². The highpermeability of the porous impaction surface 108 allows the gas-liquidstream to penetrate the media of the impaction surface 108. The highpermeability of the porous impaction surface 108 also causes furtherseparation of liquid from the gas-liquid stream beyond the separationcaused by the sharp direction change and increases the efficiency of theseparator 100.

Several properties of the media of the impaction surface 108 contributeto the separation efficiency of the gas-liquid separator 100. Generally,a higher media permeability correlates with a higher separationefficiency for a given pressure drop across the nozzle assembly 110. Inorder to vary the permeability, the fiber diameter and packing densityof the media of the impaction surface 108 can be varied. Generally, asmaller fiber diameter and a lower packing density lead to a higherseparation efficiency for an equivalent pressure drop, as describedherein below. Additionally, inertial impaction within the media of theporous impaction surface 108 is a function of both fiber diameter andthe velocity distribution of the gas-liquid stream within the media. Ahigher velocity within the media correlates to a higher separationefficiency. The highest velocity of the gas-liquid stream occurs nearestthe surface of the porous impaction surface 108. Therefore, increasedseparation efficiency can be provided by modifying properties of themedia of the porous impaction surface 108 near its surface, where thevelocity is highest and inertial impaction is greatest. In someembodiments, the fibers of the media of the porous impaction surface 108can have a diameter of between 10 micrometers and 70 micrometers and thepacking density of the media can be less than 0.2. In some embodiments,the diameter of the fibers is 18.6 micrometers and the packing densityis 0.05. In some embodiments, the porous impaction surface 108 comprisesat least one layer of fibers having low packing density upstream of atleast one layer of fibers having high permeability.

The gas-liquid stream 101 enters through the inlet 120 of the housing102, into the nozzle assembly cavity 113, and is accelerated through thenozzles 150 (e.g., from nozzle inlets 151 through nozzle outlets 152)and center nozzle 154 described further herein (e.g., through centernozzle inlets 161 through center nozzle outlets 156 and orifice 160)into the housing cavity 103 and toward the impaction surface 108. Thegas-liquid stream 101 impacts the impaction surface 108 and sharplychanges direction (e.g., from substantially parallel to the longitudinalaxis 115 to substantially perpendicular to the longitudinal axis 115),thereby removing liquid particles from the gas-liquid stream 101. A gasstream 111 results that moves around the impaction plate 118, past thelip 122, and toward the outlet 130. Separated liquid particles exit ordrain from the separator 100 through the liquid outlet 126.

Referring to FIG. 2 , the separator 100 is shown with the housing topportion 106 and the impaction plate 118 removed. In addition to thenozzles 150, the nozzle assembly 110 also includes a center nozzle 154positioned substantially along the longitudinal axis 115. The centernozzle 154 is similar to the other nozzles 150 and includes a centernozzle inlet 161 and a center nozzle outlet 156. The center nozzle 154also includes an orifice 160 formed as part of the center nozzle outlet156. The orifice 160 acts as an “always-open” feature to ensure that atleast one relatively large passage is available through which thegas-liquid stream 101 can pass. In some embodiments, one or more of thenozzles 150 may also include an orifice acting as an always-openfeature.

Referring to FIGS. 3-5 , instead of a center nozzle 154 as shown in FIG.2 , the nozzle assembly 110 can include a raised portion 170 (e.g.,raised from the top surface 123 of the nozzle assembly top portion 116)having a raised portion inlet 171 and an aperture 172. The gas-liquidstream 101 enters through the raised portion inlet 171 and exits throughthe aperture 172. The raised portion 170 is formed as part of (e.g.,integral with) the nozzle assembly top portion 116. The raised portion170 and aperture 172 act as an always-open nozzle to accelerate thegas-liquid stream 101 through the nozzle assembly 110. The raisedportion 170 is raised from the top surface 123 of the nozzle assemblytop portion 116 such that the distance between the aperture 172 (e.g.,outlet) and the impaction surface 108 is minimized. In this way, theraised portion 170 with the aperture 172 achieves a similar jet-surfaceimpaction distance as the other nozzles 150.

Various examples of the center nozzle are shown in FIGS. 6-13 .Referring to FIGS. 6-7 , the center nozzle 154 has a longitudinal axis165 and a circular orifice 160 formed in the outlet 156 and centeredaround the longitudinal axis 165. The orifice 160 is cut in such a waythat the direction of flow through the orifice 160 is substantiallyperpendicular to the longitudinal axis 165 of the center nozzle 154. Thecenter nozzle 154 includes a body 174 having an inset portion 162 havinga top inset surface 164 and a bottom inset surface 166. Referring backto FIG. 1 , the center nozzle 154 is inserted into the nozzle assemblytop portion 116 at the inset portion 162, with the top inset surface 164contacting the top surface 123 of the nozzle assembly top portion 116and the bottom inset surface 166 contacting the inner surface 117 of thenozzle assembly top portion 116.

Referring to FIGS. 8-9 , the center nozzle 254 has a longitudinal axis265 and an orifice 260 formed in the outlet 256 and centered around thelongitudinal axis 265. The orifice 260 is diamond shaped. The orifice260 is cut in such a way that the direction of flow through the orifice260 is substantially perpendicular to the longitudinal axis 265 of thecenter nozzle 254. The center nozzle 254 includes a body 274 having aninset portion 262 having a top inset surface 264 and a bottom insetsurface 266. Referring back to FIG. 1 , the center nozzle 254 isinserted into the nozzle assembly top portion 116 at the inset portion262, with the top inset surface 264 contacting the top surface 123 ofthe nozzle assembly top portion 116 and the bottom inset surface 266contacting the inner surface 117 of the nozzle assembly top portion 116.

Referring to FIGS. 10-11 , center nozzle 354 has a longitudinal axis 365and an orifice 360 formed in the outlet 356 and centered around thelongitudinal axis 365. The orifice 360 is oval-shaped. The orifice 360is cut in such a way that the direction of flow through the orifice 360is substantially perpendicular to the longitudinal axis 365 of thecenter nozzle 354. The center nozzle 354 includes a body 374 having aninset portion 362 having a top inset surface 364 and a bottom insetsurface 366. Referring back to FIG. 1 , the center nozzle 354 isinserted into the nozzle assembly top portion 116 at the inset portion362, with the top inset surface 364 contacting the top surface 123 ofthe nozzle assembly top portion 116 and the bottom inset surface 366contacting the inner surface 117 of the nozzle assembly top portion 116.

Referring to FIGS. 12-13 , the center nozzle 454 has a longitudinal axis465 and an orifice 460 formed in the outlet. The outlet is formed by afirst slot 456 and a second slot 458. From the top view shown in FIG. 12, the first slot 456 and the second slot 458 are substantiallyperpendicular to each other such that an “X” shape is formed. Theorifice 460 is circular in shape and is centered around the longitudinalaxis 465. The orifice 460 is cut in such a way that the direction offlow through the orifice 460 is substantially perpendicular to thelongitudinal axis 465 of the center nozzle 454. The center nozzle 454includes a body 474 having a flange portion 462 having a top surface466. Referring back to FIG. 1 , the center nozzle 454 is inserted intothe nozzle assembly top portion 116, with the top surface 466 contactingthe inner surface 117 of the nozzle assembly top portion 116. In someembodiments, the center nozzle 454 does not include the orifice 460 andinstead only includes the first slot 456 and the second slot 458 in an“X” shape.

Referring to FIGS. 14-17 , an impactor separator 500 formed as part of avalve cover 502 is shown, according to an example embodiment. The valvecover 502 includes a bottom portion 504. The bottom portion 504 includesan inlet 520 for receiving a gas-liquid stream. A nozzle assembly 510 ispositioned within the valve cover 502. The nozzle assembly 510 includesmultiple nozzles 550 each including a nozzle inlet 551 and a nozzleoutlet 552. The depicted nozzles 550 are duckbill valves. In otherembodiments, the nozzles 550 may be of another type. Fluid flowingthrough the separator 500 enters the nozzle 550 at the nozzle inlet 551and exits the nozzle 550 through the nozzle outlet 552. The nozzles 550receive the gas-liquid stream and accelerates the gas-liquid streamthrough the nozzles 550 toward an impaction surface 508. The distancebetween the nozzle outlet 552 and the impaction surface 508 may beapproximately 2 millimeters (mm). The fluid exiting from the nozzleoutlet 552 flows in a direction substantially perpendicular to theimpaction surface 508. The impaction surface 508 is positioned on theunderside of (e.g., as part of) an impaction plate 518. The impactionsurface 508 separates liquid particles from the gas-liquid stream. Thegas-liquid stream impacts the impaction surface 508 and sharply changesdirection. A gas stream results that moves around the impaction plate518. In addition to the nozzles 550, the nozzle assembly 510 includes araised portion 570 having an aperture 572. The raised portion 570 isformed as part of (e.g., integral with) the nozzle assembly 510. Theraised portion 570 and aperture 572 act as an always-open nozzle toaccelerate the gas-liquid stream through the nozzle assembly 510. Thegas-liquid stream enters through the raised portion inlet 571 and exitsthrough the aperture 572. The diameter of the aperture 572 may beapproximately 3.5 mm.

Referring to FIGS. 18-19 , a representation of a computational fluidanalysis of the fluid flow through a nozzle (e.g., nozzle 150) is shown,according to an example embodiment. As shown in FIG. 18 , the fluid flow602 is directed toward the impaction surface 604 after the fluid exitsthe nozzle. The fluid flow results in a rectangular impaction patch ofapproximately 4:1 length-width ratio. As shown in FIG. 19 , in someembodiments, the nozzles are positioned with the outlet slit orientationpointed radially toward the centerline (or longitudinal axis 115). Inthis way, the least possible jet interaction and the least hindrance ofthe center jet flow occurs.

Referring to FIG. 20 , a graph 700 illustrating the effect of arectangular nozzle aspect ratio on the Stokes number is shown, accordingto an example embodiment. As shown by the line graph 706, as the nozzleaspect ratio 702 increases (up to approximately 30:1), the Stokes number704 increases. For example, the Stokes number 704 for a nozzle aspectratio of 1:1 (for a circular nozzle orifice) is approximately 0.24 andthe Stokes number 704 for a nozzle aspect ratio of 10:1 (for arectangular nozzle orifice) is approximately 0.45.

Referring to FIGS. 21-22 , a separator 800 is shown which includesmultiple nozzles 850 having outlets 852. As shown in FIG. 21 , thenozzles are shown partially opened at a flowrate of approximately 600liters/minute.

Referring to FIG. 23 , a graph 900 illustrating the effect of variousimpactor nozzle types on pressure drop 904 relative to fluid flowrate902 is shown, according to an example embodiment. A fixed impactor graph906, a hybrid graph 908, and a duckbill valve graph 910 are shown. Asshown, most of the engine life is spent in the low range 912 and aworn-out engine pressure drop limit is shown at 914. The presence of analways-open orifice feature shifts the linear pressure drop response ofthe duckbill valve to a slight second order, but is still less than thepure quadratic response of a fixed impactor. The higher the pressuredrop, the higher the separation efficiency. Thus, the duckbill valvegraph 910 illustrates the highest efficiency, and the hybrid graph 908illustrates a higher efficiency than the fixed impactor graph 906, but alower efficiency than the duckbill-alone valve graph 910.

Referring to FIG. 24 , a graph illustrating the effect of variousimpactor nozzle types on efficiency 1004 relative to fluid flowrate 1002is shown, according to an example embodiment. A fixed impactor graph1006, a first duckbill graph 1008, a second duckbill graph 1010, and athird duckbill graph 1012 are shown. As illustrated, impactors usingduckbill valves improve significantly upon the efficiency of the fixedimpactor, with a similar maximum pressure drop specification at peakflow. The improvement is especially significant in the lower flowrateranges where an engine will spend the majority of its life.

It should be noted that any use of the term “example” herein to describevarious embodiments is intended to indicate that such embodiments arepossible examples, representations, and/or illustrations of possibleembodiments (and such term is not intended to connote that suchembodiments are necessarily extraordinary or superlative examples).

The terms “coupled” and the like as used herein mean the joining of twomembers directly or indirectly to one another. Such joining may bestationary (e.g., permanent) or moveable (e.g., removable orreleasable). Such joining may be achieved with the two members or thetwo members and any additional intermediate members being integrallyformed as a single unitary body with one another or with the two membersor the two members and any additional intermediate members beingattached to one another.

It is important to note that the construction and arrangement of thevarious example embodiments are illustrative only. Although only a fewembodiments have been described in detail in this disclosure, thoseskilled in the art who review this disclosure will readily appreciatethat many modifications are possible (e.g., variations in sizes,dimensions, structures, shapes and proportions of the various elements,values of parameters, mounting arrangements, use of materials, colors,orientations, etc.) without materially departing from the novelteachings and advantages of the subject matter described herein. Forexample, elements shown as integrally formed may be constructed ofmultiple parts or elements, the position of elements may be reversed orotherwise varied, and the nature or number of discrete elements orpositions may be altered or varied. The order or sequence of any processor method steps may be varied or re-sequenced according to alternativeembodiments. Additionally, features from particular embodiments may becombined with features from other embodiments as would be understood byone of ordinary skill in the art. Other substitutions, modifications,changes and omissions may also be made in the design, operatingconditions and arrangement of the various example embodiments withoutdeparting from the scope of the present invention.

Accordingly, the present disclosure may be embodied in other specificforms without departing from its spirit or essential characteristics.The described embodiments are to be considered in all respects only asillustrative and not restrictive. The scope of the disclosure is,therefore, indicated by the appended claims rather than by the foregoingdescription. All changes which come within the meaning and range ofequivalency of the claims are to be embraced within their scope.

What is claimed is:
 1. An impactor separator comprising: a housingcomprising an inlet receiving a gas-liquid stream and an outletexpelling a gas stream; an impaction surface positioned within thehousing and configured to separate liquid particles from the gas-liquidstream; and a nozzle assembly positioned within the housing having alongitudinal axis and comprising a nozzle assembly housing portion and aplurality of nozzles extending through the nozzle assembly housingportion, each of the plurality of nozzles having a nozzle inlet and anozzle outlet, the plurality of nozzles comprising: a central duckbillvalve disposed along the longitudinal axis, the central duckbill valvehaving an always-open orifice, and a plurality of duckbill valvesdisposed around the central duckbill valve; wherein the gas-liquidstream enters into the nozzle assembly housing portion, flows into theplurality of nozzles through the nozzle inlets and exits the pluralityof nozzles through the nozzle outlets, wherein the plurality of nozzlesaccelerates the gas-liquid stream toward the impaction surface.
 2. Theimpactor separator of claim 1, wherein the central duckbill valve isformed integral with the nozzle assembly housing portion.
 3. Theimpactor separator of claim 1, wherein the always-open orifice iscircular in shape.
 4. The impactor separator of claim 1, wherein thealways-open orifice is oval in shape.
 5. The impactor separator of claim1, wherein the nozzle outlet of the central duckbill valve includes afirst slot and a second slot, the first slot substantially perpendicularto the second slot.
 6. The impactor separator of claim 5, wherein thenozzle outlet further comprises an aperture formed in the center of thenozzle outlet.
 7. An impactor separator formed as part of a valve cover,the impactor separator comprising: a nozzle assembly positioned withinthe valve cover having a longitudinal axis, a bottom portion of thevalve cover comprising an inlet receiving a gas-liquid stream, andcomprising a plurality of nozzles having a nozzle inlet and a nozzleoutlet, the plurality of nozzles comprising: a central duckbill valvedisposed along the longitudinal axis, the central duckbill valve havingan always-open orifice, and a plurality of duckbill valves disposedaround the central duckbill valve; and an impaction plate having animpaction surface structured to separate liquid particles from thegas-liquid stream; wherein the gas-liquid stream enters into the valvecover, flows into the plurality of nozzles through the nozzle inlets andexits the plurality of nozzles through the nozzle outlets, the pluralityof nozzles accelerating the gas-liquid stream toward the impactionsurface.
 8. The impactor separator of claim 7, wherein the centralduckbill valve is formed integral with the nozzle assembly.
 9. Theimpactor separator of claim 7, wherein the always-open orifice iscircular in shape.
 10. The impactor separator of claim 7, wherein thealways-open orifice is oval in shape.
 11. The impactor separator ofclaim 7, wherein the nozzle outlet of the central duckbill valveincludes a first slot and a second slot, the first slot extendingsubstantially perpendicular to the second slot.
 12. The impactorseparator system of claim 11, wherein the nozzle outlet furthercomprises an aperture formed in the center of the nozzle outlet.
 13. Anozzle assembly for use with an impactor separator comprising: a nozzleassembly housing portion having a longitudinal axis; and a plurality ofnozzles extending through the nozzle assembly housing portion, each ofthe plurality of nozzles having a nozzle inlet and a nozzle outlet, theplurality of nozzles comprising: a central duckbill valve disposed alongthe longitudinal axis, the central duckbill valve having an always-openorifice, and a plurality of duckbill valves disposed around the centralduckbill valve; wherein one of the plurality of nozzles is positionedalong the longitudinal axis and comprises an always-open orifice. 14.The nozzle assembly of claim 13, wherein the central duckbill valve isformed integral with the nozzle assembly housing portion.